Bulldozer isn't as good as AMD said it was going to be! The sky is falling!!!
Seriously guys, the system he described should be able to run WoW just fine. My three year old CPU handles our 25m raids (including Ultraxion while logging in Skada) without any issues. While the hardware isn't top notch, or bought under the best advice, it's still sufficient for WoW. There is no reason the OP should be getting the performance issues described.
To the OP - make sure that your drivers are up to date (double check this), and that your CPU and GPU temperatures are within acceptable limits (60C for CPU, 90C for GPU). If you need software to keep an eye on the temperatures, download and install
HWMonitor. Run that in the background as you load up WoW. After you're done, look at the maximum temperatures recorded. If the CPU is getting too hot, it might be throttling itself (which would cause FPS issues).